In these austere times, I'ld like to use up some of the many tins of
paint I have in the shed, rather than go out and buy more.

I've got to prime the fresh wooden slats (pine) of a garden seat, before
giving them several coats of gloss paint.

I've got no primer in the shed, but I do have a whole tin of
"Stainblock" and a whole tin of "AquaSeal Damp Proofer".

Can I use either of these as the primer?

Or will they so seal up the wood that it will rot inside the coating?

Thanks.

Eddy.